EMYDID^. 



32! 



The neural bones are of moderate width; the table shows their dimensions: 

 The length of the nuchal was close to 56 mm.; its width along the free border about 42 mm.; 

 its greatest width is 67 mm. The free border of the nuchal and those of the first peripherals 



are acute, especially as shown by No. 6089; but the bone thickens rapidly toward the costals. 

 The thickness of the first and second peripherals at their articulation is 20 mm. 

 The dimensions of the peripherals are shown in the table above. 



The upper surface of the carapace is nearly smooth, but is relieved by striation and faint 

 lines of growth; but these are not so distinct as they are on Cope's type of E. septaria. The 

 second and third vertebral scutes are urn-shaped, expanded in front, and narrowed behind. 

 The first vertebral is the broadest. The dimensions of vertebral and marginal scutes are given 

 in the second table above. 



C.p.S 



per. 6. 



FIGS. 417 AND 418. Echmatemys septaria. X}. No. 6085 A. M. N. H. 



417. Upper surface of free border of hinder lobe of plastron. 



418. Section across shell at the inguinal buttresses. Shows the sixth peripheral {per. 6), the 



fifth costal plate (<r. p. 5), and the right and left inguinal buttresses (r. ing., I. ing). 



It will be observed that the second marginal is unusually high. This is true in both No. 

 6085 and No. 6089. As shown by both these specimens, the costo-marginal sulci run near the 

 costo-peripheral sutures ; in No. 6085, a few millimeters below ; in No. 6089, on the sutures. 



The plastron (fig. 416) has a total length of 345 mm. The anterior lobe is 95 mm. long and 

 133 mm. wide at the base, the length thus being 71 per cent, of the width. The entoplastron is 

 50 mm. long and 53 mm. wide. Immediately in front of the axillary notch the lobe narrows a 



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